Plastics, or polymers, are used in a variety of products and applications ranging from the simple pen to the complicated wing of an aircraft. Different types of plastic or polymers, as they are technically known, generally have different mechanical, chemical, and electrical properties that allow plastics to be used in many applications. Plastics are typically formed into a product through a molding process, such as transfer molding, injection molding, sheet molding, or blow molding.
For example, plastics are used extensively in the computer and semiconductor industry in a wide variety of applications. One such application is the encapsulation of semiconductor devices, particularly integrated circuits. Encapsulating a semiconductor device in plastic materials protects the device from environmental damage and also provides structural strength to the semiconductor device.
A molding process typically includes a mold containing mold cavities. A system of passages, or runners, is generally contained within the mold and connects a reservoir, or pot, to each or multiple mold cavities. The molding material is non-solidified in the pot during the molding process. Prior to the molding process, the molding material may be a solid or liquid. A plunger sized to fit within the pot may be used to force the non-solidified molding material from the pot through the runner system into the mold cavities. The non-solidified molding material solidifies or hardens and a final molded product, or package, is removed from the mold.
Conventional molding material packaging methods and systems suffer from numerous disadvantages. One disadvantage of conventional molding material packaging methods and systems that use plastic wrappers or thin films is that low viscosity molding materials, such as liquids and putties, cannot be prepackaged into packages that can be placed into the pot of a mold. For example, the plastic wrapper may be torn or not properly sealed, allowing contaminates such as air and moisture to enter the package. A further disadvantage is that during the molding process a prepackaged molding material package may not collapse uniformly in the pot during transfer and may become damaged and leak during the molding process. A leak in the package often requires the pot and plunger to be cleaned before additional molding operations are performed. Problems in the transfer of prepackaged molding materials often causes problems in the final molded product. For example, contamination and incomplete filling of the mold cavities can result in internal voids and defects that often degrade the mechanical, electrical, and chemical properties, as well as the appearance, of the final molded product. In addition, it may be difficult to control the weight and volume of the molding material initially placed into the pot of the mold. Controlling the weight and volume of the molding material initially placed into the pot of the mold is important to the molding process because it helps prevent under filling or over filling of the mold cavities with molding material.